Czapski, PawełKubiak, Tomasz2017-09-052017-09-052016Mechanics and Mechanical Engineering Vol. 20, No. 2, 2016, str. 79–951428-1511http://hdl.handle.net/11652/1648This paper presents selected cases of inapplicability of theory based methods of determining critical loads in thin – walled, composite tubes. 8th layered composite tubes with square cross-section were being subjected to static compression and in order to register experimental data two measuring equipment were employed: strain-gauges and Digital Image Correlation system ARAMIS R ⃝ . When measurement data were collected five different theory based methods were applied in order to determine critical loads. Cases where it was impossible to apply certain methods or some doubts about correctness of the results occurred were presented and analyzed. Moreover in cases where it was possible, the theory was equivalently transformed, in such a way to fit experimental data and calculate the critical loads.enbuckling experimentscritical load determinationsstability investigationsstrain–gaugesDigital Image Correlationwyboczeniekorelacja obrazu cyfrowegobadanie stabilnościczujniki odkształceńArtykuł